Control mechanism for lock stitch sewing machines



Sept. 10, 1963 s. .1. KETTERER CONTROL MECHANISM 'FOR LOCK STITCH smwmc MACHINES Fi led Aug. 25. 1961 4 Sheet s Sheet 1 INVEN TOR. STANLEY J. KETTERER WI TNESS ATTORNEY 4 Sheets-Sheet 2 I S. J. KETTERER r||| r l I l I I I ll CONTROL MECHANISM FOR LOCK STITCH SEWING MACHINES ATTORNEY STANLEY J. KETTERER BY WITNESS Sept. 10, 1963 S. J- KETTERER CONTROL MECHANISM FOR LOCK STITCH SEWING MACHINES '4 Sheets-Sheet 5 Filed Aug. 25, 1961 Fig. 6.

WITNESS ATTORNEY ep 1953 5. J. KETTERER CONTROL MECHANISM FOR LOCK STITCH SEWING MACHINES 4 Sheets-Sheet 4 Filed Aug. 25. 1961 INVENTOR. STANLEY J. KETTERER BY ATTORNEY WITNESS wa zi 6 ,1

United States Patent 3,103,189 CONTROL MECHANISM FOR LOCK STITCH SEWING MACHINES Stanley J. Ketterer, Morris Plains, N.J., assignor to The Singer Company, a corporation of New Jersey Filed Aug. 25, 1961, Ser. No. 133,911 7 Claims. (Cl. 112-184) This invention relates to lock stitch sewing machines having a mechanism for replenishing thread on a bobbin in place in the loop taker during continued interrelated motion of the needle and loop taker of the sewing madhine as is required for the formation of lock stitches. More particularly this invention relates to a novel and improved control unit for initiating and controlling the amount of thread replenished on a bobbin in place in a sewing machine loop taker.

It is an object of this invention to provide a control unit capable, in a single operator influenced manipulation, of initiating thread replenishment and of selectively controlling the amount of thread to be replenished on a bobbin in place in a sewing machine loop taker.

It is also an object of this invention to provide for a control unit of the above character, a novel and improved drive means for indexing said control unit in timed relation with said sewing machine to control the amount of thread replenished on a bobbin in place in a sewing machine loop taker.

A further object of this invention is to provide a novel arrangement for simultaneously rendering the needle thread tensioning device and the work feeding mechanism ineffective upon initiation of thread replenishment and for automatically reestablishing the needle thread tensioni-ng device and work feeding mechanism to eifectiveness upon termination of thread replenishment of a bobbin in place in the loop taker.

With the above and other objects and advantages in view as will hereinafter appear, this invention comprises the devices, combinations, and arrangements of par-ts hereinafter described and illustrated in the accompanying drawings of a preferred embodiment in which:

FIG. 1 represents a front elevational view of a sewing machine having my invention applied thereto and with portions of the sewing machine frame being broken away to expose the mechanism therein,

FIG. 2 is an enlarged cross sectional view of a portion of the sewing machine and the control unit of this invention taken substantially along line 22 of FIG. 1 with the parts illustrated in the positions occupied during sewing and with the drive for the control unit disengaged,

FIG. 3 represents a detached view of those parts of FIG. 1 which are concerned with driving the control unit and with these parts illustrated in operative relation for driving the control unit,

FIG. 4 is an enlarged cross sectional view through the control unit taken substantially along line 44 of FIG. 2 and, as in FIG. 2, illustrating the parts in the positions occupied during sewing,

FIG. 5 represents a detached view of those parts of FIG. 4 which are connected with engaging the drive for the control unit with these parts illustrated in operative relation for engaging the drive,

FIG. 6 is an enlarged cross sectional view of the control unit taken substantially along line 6--6 of FIG. 1,

FIG. 7 represents a top plan view of the sewing machine .loop taker including portions of the sewing machine bed the control unit of this invention is illustrated as applied "ice comprises a frame including a work supporting bed 11, a standard 12 and bracket arm 13 extending from the standard over the bed. Slidable endwise in the bracket arm is a needle bar 14 carrying an eye pointed thread carrying needle 15. The needle is reciprocated and a take up lever 16 carried in the bracket arm is oscillated in timed relation therewith by operative connections (not shown) with a main shaft 17 journaled lengthwise in the bracket arm. Also supported on the bracket arm is a thread tensioning device 18 through which the needle thread is directed from a supply thence to the take up lever and then to the eye of the needle in the conventional threading of the needle of a lock stitch sewing machine.

The main shaft 27 carries a balance wheel 20 and also a driving gear 21 by which the sewing machine may be driven from an operator influenced electric motor (not shown) although any equivalent driving means may be employed to operate the sewing machine main shaft.

The sewing machine preferably includes a work feeding mechanism of the conventional four motion drop feed variety, of which the feed and return motions are unparted from a feed advance eccentric 22 on the main shaft by way of a pitman 23 controlled by a slide block 24 carried in a stitch length adjusting lever 25 on the machine standard. The feed lift motions are unparted from a feed lift eccentric 26 on the main shaft by way of a feed lift pitman 27 in the standard to a pin 28 carried on a rock arm 29 fast on a feed lift rock shaft 30 journaled beneath the bed. As illustrated in FIGS. 2 and 3, the feed lift pitman 27 is formed with a T shaped slot embracing the pin 28, of which slot a limb 31 extends transversely of the pitman and a limb 32 extends lengthwise of the pitman. A spring 33 acting between the pitman and the bed serves to bias the pin 28 into the transverse limb 31 of the slot thus operatively connecting the pitman with the feed lift rock arm. As illustrated in FIG. 3, when the pitman is shifted toward the left carrying the pin 28 into the lengthwise limb 32 of the slot, the pitman 27 will be inelfeotive to influence feed lift motion and the work feed mechanism will be thrown out of operation.

Driven at a speed of two revolutions for each reciprocation of the needle by meshing spiral bevel gears 40-40 on the main shaft and on a shaft 41 journalled vertically in the standard, by spiral bevel gears 4242 on the standard shaft and on a bed shaft 43, and by spiral bevel gears 4444 on the bed shaft and a hollow-vertical axis loop taker shaft 45, is a loop taker indicated generally as 46. By means of the drive described above, the needle, take up, loop taker and work feeding mechanism are actuated in timed relation as is required for the formation of lock stitches.

The loop taker 46 disclosed in the accompanying drawings is of the type referred to in the art as a rotary hook, although the control unit of this invention would be useful with other types of lock stitch loop takers. Reference is made to my co-pending United States patent application Serial No. 75,387, filed December 12, 1960 which discloses a rotary hook which differs only slightly from that illustrated in the accompanying drawings and which may be referred to particularly for a detailed explanation of the manner in which the parts cooperate in the process of replenishment of locking thread on a bobbin in place in the loop taker.

As illustrated in FIGS. 7 and 8, the loop taker 46 comprises a cup-shaped body portion 50 formed with an internal bearing rib 51 on which is journaled the complement-a1 bearing raceway 53 of a bobbin case 54 constrained in the loop taker body portion and restrained from rotation by means of a bifurcate rotation restraining arm 3 57 on the bobbin case. Journaled in the bobbin case is a bobbin 58 having an axial pin 59 which is embraced by a radial bobbin constraining arm 60 pivoted on the bobbin case.

Disposed between the loop taker and the bobbin with in the cup-shaped loop taker body portion is a bobbin winding member 61 which is fast on a rod 62 slidable axially in the hollow loop taker shaft 45. The bobbin winding member is formed with a radial arm 63 project ing into an aperture 64 in the loop taker body portion thus locking the bobbin winding member for rotation with the loop taker. The bobbin winding member is formed with a thread clamping finger 65 disposed adjacent to a thread seizing beak 66 formed on the loop taker body portion, and is also formed with a raised thread guiding rib 67 disposed adjacent to the bobbin to deflect into the bobbin a limb of thread seized by the beak 66 and gripped thereon by the thread clamping linger 65.

A drive pin 70 carried by the bobbin winding member cooperates with one of a plurality of sockets 71 formed in the bobbin to engage and drive the bobbin with the loop taker when the bobbin winding member is raised into effective position. The bobbin winding member is raised and lowered in accordance with the position of a thread replenishing lever 72 fulcrumed at 73 beneath the bed and carrying a leaf spring 74 which underlies the rod 62 beneath the loop taker shaft. The rod 62 carries fast thereon a camdisk 75 which cooperates with a finger 76 secured beneath the bed to shift the bobbin winding member momentarily downwardly out of fully effective bobbin winding position during each rotation of the loop taker for the purpose of releasing and reengaging the thread clamping finger 65 at precisely the proper time during each rotation of the loop taker as to ensure that a thread seized by the beak 66 will .be gripped by the thread clamping finger 65 regardless of the time during any rotation of the loop taker that the thread replenishing lever 72 is turned into effective position.

In sewing, when the bobbin winding member is shifted downwardly out of engagement with the bobbin, the loop taker and needle cooperate in the conventional manner to manipulate loops of needle thread about the bobbin thus to concatenate needle thread with thread carried on the bobbin in the formation of lock stitches. When the thread replenishing lever 72 is turned so as to elevate the bobbin winding member 61 into engagement with the bob bin, a loop of needle thread seized by the loop taker beak will be clamped on the loop taker by the finger 65, the clamped thread loop will be guided into the bobbin by the thread guiding rib 67 and the bobbin will be rotated by the drive pin 70 to wind thread thereon.

It is preferable during the bobbin thread replenishing operation for the needle thread tension device 18 to be released to lessen the drag on the thread being wound on the bobbin, and also for the work feeding mechanism to be rendered ineffective so that work may remain uninfluenced at the stitching point during thread replenishment.

It is necessary, there-fore, that provision be made for influencing the thread replenishing lever, the throw out of the work feed, and the release of the needle thread tensioning device to initiate bobbin thread replenishment. It is also necessary, if the amount of thread to be replenished is to be regulated, that means be provided for controlling the period during which the thread replenishing lever and feed throw out and needle thread tension releasing means remain effective.

As disclosed in my above mentioned copending United States application Serial No. 75,387 two separate operator influenced means are provided one for initiating thread replenishment and a separately influenced means for controlling the amount of thread replenished.

With the present invention, as will now be described, a single operator influenced member serves not only to 4 initiate winding but also to regulate the amount of thread to be wound.

Secured in a seat 80 formed in the front Wall of the sewing machine standard is a bearing block 81. Journaled in the bearing block is a shaft 82 having fast thereon an operator influenced knob 83 formed with a skirt 34 extending behind an escutcheon plate 85 and visible through a window 87 formed in the escutcheon plate. Indicia 88 provided on the knob skirt cooperates with a mark 89 formed on the escutcheon plate to indicate the angular position of adjustment of the knob. The indicia preferably includes a mark such as O indicative of an at rest position of the knob in which sewing will take place, a small angular segment marked with an arrow head at each extremity to indicate the movement of the knob required to initiate bobbin thread replenishment, and evenly spaced marks about the remaining periphery of the skirt to indicate the various amounts of thread which will be wound on the bobbin corresponding to the various possible positions of initial adjustment of the knob. In order to operate the machine fitted with the control unit of this invention, all that is necessary is first to position the knob 83 such that the amount of thread desired on the bobbin is indicated through the window 87 and then to actuate the machine. The indicated amount of thread will be wound on the bobbin following which the machine will proceed automatically to form lo ck stitches.

Referring to FIGS. 4, 5 and 6, the mechanism for accomplishing such control comprises a collar 90 [fast on the shaft 82 and formed with a cam notch 91. A lever 92 fulcrumed :on a pin 93 set into the bearing block 81 is formed with a shoulder 94 adapted to track the collar 90 and to seat in the cam notch 91 when in registry therewith. A bifurcate arm 95 on the lever 92 loosely embraces a pin 96 on the bearing block so as to maintain the lever within a desired range of movement. The lever 92 is formed with a lever arm. 97 which overlies a projecting arm 98 formed ona link 99 disposed substantially vertically within the machine standard. The link 99 is pivotally supported at the top on one end of a lever 100 fulcrumed at 101 within the bracket arm and pivotally connected at the other end to a thread tension device releasing slide bar 182. The link 99 at its lower extremity is formed with an offset arm 103 pivotally secured at 104 to the thread replenishing lever 72. The link 99 is also formed with a finger 105 disposed to abut a cam track 106 formed along one side of the feed lift pitman 27. A spring 107 arranged between the lever 100 and the bracket arm may be employed to bias the link 99 upwardly into the position of parts illustrated in FIGS. 1, 2 land 4 in which the shoulder 94 is seated in the cam notch 91 of the control unit and in which sewing will occur. When the knob 83 is turned and the cam notch 91 moved out of registry with the shoulder 94, as illustrated in FIG. 5, the lever arm 97 will depress the link 99 causing the thread tension device to be released, the thread replenishing lever 72 to be shifted into effective position and the feed lift pitman to be shifted as illustrated in FIG. 3 to a position in which the pin 28 is disposed in the lengthwise link 32 of the slot so as to render the work feed mechanism inoperative.

A plunger 110 is slidably carried transversely of the feed lift pitman 27 and biased axially by means of a spring 111. When the feed lift pitman is shifted into the position illustrated in FIG. 3 and bobbin thread replenishment is initiated, the plunger 110 will be shifted with the feed lift pitman into a position of interference with a lever arm 112 formed on a pawl carrying lever 1 13 loosely journaled on the shaft 84. The pawl oarrying lever is formed with a bifiurcate arm 114 embracing the pin 96 so as to maintain the pawl carrying lever within a desired range of movement such that a slot 115 formed in the lever arm 112 will be maintained within the range of motion of the plunger 110 as the plunger moves with the feed lift pitman. The plunger 110 will, therefore, within one revolution of the main shaft 17 register with and be moved into the slot 115 by the spring 111 so that the pawl carrying lever 113 will thereafter be oscillated by the action of the feed lift pitman 27.

Pivotally secured on a shouldered fulcrum screw 116 on the pawl carrying lever are a pair of pawls 117 and 118 each biased by a spring 119, 120 toward the teeth of a ratchet wheel 121 fast on the shaft 84. The pawlls 117 and 118 are spaced apart peripherally of the ratchet Wheel 121 an amount equivalent to one half the distance between successive teeth on the ratchet wheel, the ratchet wheel teeth being preferably of that size with respect to the movement of the feed lift pitman that the pawls 117, 1118 together index one ratchet tooth for every two revolutions of the main shaft 17.

The machine operator, by turning the knob 83 thus not only initiates replenishment of the thread on the bobbin but also initiates an automatic indexing of the control unit toward the at rest position in which the machine will automatically revert to conventional lock stitch formation. Moreover, the operator, in turning the knob 83 can select the distance from the at rest position at which the bobbin thread replenishing operation is to commence thereby to control the amount of thread which will be replenished on the bobbin.

Having set forth the nature of this invention, what is claimed herein is:

1. In a sewing machine having a frame, -a thread carrying need-1e carried in said frame, a loop-taker journaled in said frame, a thread carrying bobbin journaled in said loop-taker, a drive means operatively interconnecting said needle and loop-taker for motion in timed relation as is required for the formation of lock stitches, and means associated with said loop-taker for replenishing thread on said bobbin in place in said loop-taker during motion of said needle and loop-taker as is required for the formation of lock stitches the improvement comprising, a control member having an at-lrest position, means shi-ftably supporting said control member relatively to said sewing machine frame for movement into and out of said at-rest position, means associated with said control member for rendering said thread replenishing means ineffective when said control member occupies said at-rest position and effective while said control member is disposed out of said at-rest position, operator influenced means for shifting said control member from said at-rest position and to any selected one of a range of distances therefrom, an indexing mechanism operated by said drive means for said needle and loop-taker and operative to return said control mechanism to said at-rest position at a rate proportional to the speed of operation of said drive means, and means associated with said control member for rendering said indexing mechanism effective upon movement of said control member out of said at-rest position.

2. In a sewing machine having a frame, a thread carrying needle carried in said frame, a loop-taker journaled in said frame, a thread carrying bobbin journaled in said loop-taker, a drive means operatively interconnecting said needle and loop-taker for motion in timed relation as is required for the formation of lock stitches, and means associated with said loop-taker for replenishing thread on said bobbin in place in said loop-taker during motion of said needle and loop-taker as is required for the formation of lock stitches the improvement comprising, a control member journaled in said sewing machine frame, means defining an at-rest angular position of said control member relatively to said sewing machine frame, means associated with said control member for rendering said thread replenishing means ineffective when said control member occupies said at-rest angular position and effective while said control member is turned relatively to said sewing machine frame out of said at-rest angular position, operator influenced means for shifting said control member angularly in one direction of rotation relatively to said sewing machine frame (from said at-rest position to any selected one of a range of angular distances therefrom, an indexing mechanism operated by said drive means for said needle and loop-taker and operative to shift said control member in said one direction of rotation into said at-rest position at a rate proportional to the speed of operation of said drive means, and means associated with said control member for rendering said indexing mechanism effective upon angular movement of said control member out of said atrest position.

3. In a sewing machine as set forth in claim 1 in which said frame includes a work supporting bed in which said loop taker is journaled, a standard nising from said bed, and a bracket arm in which said needle is carried extending from said standard and overhanging said bed, said means supporting said control member being arranged tosustain said control member on said standard above said work supporting bed.

4. In a sewing machine having a frame including a work supporting bed, a lcop-taker journaled in said bed, a thread carrying bobbin journaled in said loop-taker, a standard rising from said bed, a bracket arm extending from said standard and overhanging said bed, a thread carrying needle carried in said bracket arm, needle thread tensioning means carried on said bracket arm, means including a lever :fulcrumed in said bracket arm for releasing said needle thread tensioning means, a drive means operatively interconnecting said needle and said looptaker for motion in timed relation as is required for the formation of lock stitches, means associated with said loop-taker for replenishing thread from said needle on said bobbin in place in said loop-taker during motion of said needle and loop taker as is required for the formation of lock stitches, and a lever fulcrumed in said bed for operating said thread replenishing means, the improvement comprising, a control member shiftably supported on said standard and having an at-rest position relatively to said frame, operator influenced means for shifting said control member from said at-rest position and to any selected one of a range of distances from said at-rest position, a link disposed in said standard pivotally connected to Said thread tension releasing lever in said bracket arm and to said thread replenishing lever in said bed, means carried by said control means for shifting said link to render said thread replenishing means effective and to release said needle thread tensioning means while said control member occupies a position out of said at-rest position, an indexing mechanism operated by said drive means for said needle and loop-taker and operative to return said control mechanism to said at-rest position at a rate proportional to the speed of operation of said drive means, and means carried by said link for rendering said indexing mechanism effective upon movement of said control member out of said at-rest position.

5. In a sewing machine as set forth in claim 1 including a work feeding mechanism and a member having an operative engagement with said work feeding mechanism and actuated by said drive means for operating said Work feeding mechanism, and in which said means for rendering said indexing mechanism effective comprises a means carried by said control member for shifting said work feeding mechanism operating member out of operative engagement with said work feeding mechanism and into operative engagement with said indexing mechanism.

6. In a sewing machine as set forth in claim 2 in which said control member comprises a shaft journaled in said standard, a cam fast on said shaft, and a ratchet wheel fast on said shaft, in which said means associated with said control member for rendering said thread replenishing means eifective comprises a follower disposed tracking said cam means and linkage operatively connecting said follower with said thread replenishing means associated with said loop-taker, in which said indexing mechanism comprises a pawl means disposed in engagement with said ratchet wheel and supported for vibration on said shaft, and in which said means associated with saidcontrol member for rendering said indexing mechanism eflective comprises means shifted by said cam follower means for operatively connecting said pawl means with said drive means for said needle and loop-taker.

7. In a sewing machine having a frame, a thread carrying needle carried in said frame, a loop-taker journaled in said frame, a thread carrying bobbin journaled in said loop-taker, a drive means operatively interconnecting said needle and loop-taker for motion in timed relation as is required for the formation of lock stitches, and means associated with said loop-taker for replenishing thread on said bobbin in place in said loop taker during motion of said needle and loop-taker as is required for the formation of lock stitches the improvement comprising a control member having an at-rest position, means shiftably supporting said control member relatively to said sewing machine frame for movement into and out of said at-rest position, operator influenced means for shifting said control member from said at-rest position and to any selected one of a range of distances therefrom, means associated with said control member for rendering said thread replenishing means inefiective when said control member occupies said at-rest position, means for rendering said thread replenishing means effective when said control member is shifted into any position within said range of distances from said at-rest position, an indexing mechanism operated by said drive means for said needle and loop-taker and operative to return said control memher to said at-rest position at a rate proportional to the speed of operation of said drive means, and means associated with said control member for rendering said indexing mechanism efiective upon movement of said control member into any position within said range of distances from said at-rest position. 

1. IN A SEWING MACHINE HAVING A FRAME, A THREAD CARRYING NEEDLE CARRIED IN SAID FRAME, A LOOP-TAKER JOURNALED IN SAID FRAME, A THREAD CARRYING BOBBIN JOURNALED IN SAID LOOP-TAKER, A DRIVE MEANS OPERATIVELY INTERCONNECTING SAID NEEDLE AND LOOP-TAKER FOR MOTION IN TIMED RELATION AS IS REQUIRED FOR THE FORMATION OF LOCK STITCHES, AND MEANS ASSOCIATED WITH SAID LOOP-TAKER FOR REPLENISHING THREAD ON SAID BOBBIN IN PLACE IN SAID LOOP-TAKER DURING MOTION OF SAID NEEDLE AND LOOP-TAKER AS IS REQUIRED FOR THE FORMATION OF LOCK STITCHES THE IMPROVEMENT COMPRISING, A CONTROL MEMBER HAVING AN AT-REST POSITION, MEANS SHIFTABLY SUPPORTING SAID CONTROL MEMBER RELATIVELY TO SAID SEWING MACHINE FRAME FOR MOVEMENT INTO AND OUT OF SAID AT-REST POSITION, MEANS ASSOCIATED WITH SAID CONTROL MEMBER FOR RENDERING SAID THREAD REPLENISHING MEANS INEFFECTIVE WHEN SAID CONTROL MEMBER OCCUPIES SAID AT-REST POSITION AND EFFECTIVE WHILE SAID CONTROL MEMBER IS DISPOSED OUT OF SAID AT-REST POSITION, OPERATOR INFLUENCED MEANS FOR SHIFTING SAID CONTROL MEMBER FROM SAID AT-REST POSITION AND TO ANY SELECTED ONE OF A RANGE OF DISTANCES THEREFROM, AN INDEXING MECHANISM OPERATED BY SAID DRIVE MEANS FOR SAID NEEDLE AND LOOP-TAKER AND OPERATIVE TO RETURN SAID CONTROL MECHANISM TO SAID AT-REST POSITION AT A RATE PROPORTIONAL TO THE SPEED OF OPERATION OF SAID DRIVE MEANS, AND MEANS ASSOCIATED WITH SAID CONTROL MEMBER FOR RENDERING SAID INDEXING MECHANISM EFFECTIVE UPON MOVEMENT OF SAID CONTROL MEMBER OUT OF SAID AT-REST POSITION. 